1. Field of the Invention
This invention is related to an apparatus and method for removing particulates, ions and impurities from an engine coolant liquid. More specifically, this invention provides for an apparatus and method for removing particulates, impurities, and cations and anions from an engine coolant liquid having a freezing point depressant and situated in an internal combustion engine cooling system.
2. Description of the Prior Art
One of the biggest problems facing today's automotive and industrial shops is the disposal of hazardous waste. On Oct. 17, 1986 SARA Title III was signed into law by the U.S. Congress. Section 313 of this legislation designated ethylene glycol, the major component in antifreeze, as a toxic chemical. Furthermore, the EPA designates ethylene glycol as hazardous waste under 40 CFR 414.60. The regulatory impact on automotive service stations and other industrial shops would depend on the volume of antifreeze to be disposed of and other factors, especially when spent antifreeze has to be periodically replaced. Presently, there are but two viable options or alternatives for discarding spent antifreeze; namely, collect and store it in drums and/or pay a hazardous waste collector to transport it for disposal. Both of these options or alternatives are costly, especially when compared to disposing the spent antifreeze illegally by merely pouring it down the drain.
Antifreeze is a rather complex mixture of chemical components designed to perform the following functions in a vehicle:
(a) protect against overheating and freezing; PA1 (b) protect the many dissimilar metals within the cooling system (copper, brass, steel, iron, aluminum and lead) from corrosion; PA1 (c) buffer against acidic contamination (blow by gases, glycol degredation products); PA1 (d) prevent foaming; PA1 (e) prevent hard water scaling; PA1 (f) reduce consequences of oil fouling; and PA1 (g) protect diesel wet-sleeve liners from cavitation damage. PA1 (a) passing a liquid having ions, including nitrogen containing ions, through an ion-exchanger bed wherein at least part of the ions are removed and at least part of the nitrogen containing ions is converted into nitrogen containing compounds to produce a liquid with at least part of the ions removed and having nitrogen containing compounds; and PA1 (b) passing the produced liquid of step (a) through a means for removing nitrogen containing compounds to produce a liquid with at least part of the ions removed and with at least part of the nitrogen containing compounds removed. PA1 (a) removing, from a cooling system of an internal combustion engine to the exterior thereof, an engine coolant liquid which is situated in the cooling system of the internal combustion engine and contains particulates, ions, and nitrite ions; PA1 (b) passing the engine coolant liquid through a filtration zone wherein a majority of the particulates are removed to produce an engine coolant liquid having the ions and the nitrite ions; PA1 (c) passing the produced engine coolant liquid of step (b) through a means for removing ions wherein at least part of the ions is removed and nitrite ions are converted into nitrogen containing compounds such as nitrogen oxides, to produce a liquid containing the nitrogen containing compounds; PA1 (d) passing the produced engine coolant liquid of step (c) through a means for removing the nitrogen containing compounds wherein at least part of the nitrogen containing compounds is removed; and PA1 (e) returning subsequently the engine coolant liquid, produced from the means for removing the nitrogen containing compounds, to the cooling system of the internal combustion engine. PA1 (a) providing an engine coolant liquid having particulates, hydrocarbons, cations, anions and nitrite ions, and a freezing point depressant; PA1 (b) passing the engine coolant liquid of step (a) through a first mechanical filtering means for filtering and wherein part of the particulates are removed to produce an engine coolant liquid having residual particulates, hydrocarbons, cations, anions, nitrite ions, and the freezing point depressant; PA1 (c) passing the produced engine coolant liquid of step (b) through a zone for pumping wherein the produced engine coolant liquid of step (b) is pumped towards a chemical filtering means for filtering and wherein at least part of the hydrocarbons is to be removed; PA1 (d) passing the pumped engine coolant liquid of step (c) through a chemical filtering means for filtering and wherein at least part of the hydrocarbons is removed to produce an engine coolant liquid having residual particulates, cations, anions, nitrite ions and the freezing point depressant; PA1 (e) passing the produced engine coolant liquid of step (d) through a second mechanical filtering means for filtering and wherein at least part of the residual particulates is removed to produce an engine coolant liquid having cations, anions, nitrite ions, and the freezing point depressant; PA1 (f) passing the produced engine coolant liquid of step (e) through a strong acid cation exchange bed in the hydrogen form wherein at least part of the cations is removed and at least part of the nitrite ions is converted into a gas containing nitrogen and selected from the group consisting of nitric oxide, nitrogen dioxide, and mixtures thereof, to produce an engine coolant liquid having anions, the gas containing nitrogen, and the freezing point depressant; PA1 (g) passing the produced engine coolant liquid of step (f) through a strong base anion exchange bed in the hydroxide form wherein at least part of the anions is removed to produce an engine coolant liquid having the gas containing nitrogen and the freezing point depressant; and PA1 (h) passing the produced engine coolant liquid of step (g) through a bed of activated particulate carbon wherein at least part of the gas containing nitrogen is removed to produce an engine coolant liquid having the freezing point depressant.
All of those functions are important and demanding on an engine liquid coolant. Each must be specifically considered or, at some point, engine damage will occur, resulting in sometimes costly repair. To obtain the optimum protection, the engine liquid coolant must have a well balanced additive package that may consist of up to 15 different inhibitors in addition to the more commonly known components such as water, ethylene glycol, and dye. Most inhibitors are introduced as sodium or potassium salts and usually are specific in providing corrosion inhibition to one or two metals. As antifreeze ages and accumulates miles or hours in a vehicle's cooling system, it also accumulates many different types of contaminants. These include oil from leaking oil coolers and water pump lubricants, corrosion products in the form of metal ions and metal hydroxides (e.g. aluminum hydroxide can be produced through aluminum cylinder head corrosion), and acids from blowby gasses and glycol degredation products such as glycolic, formic, oxalic, acetic acid. Other impurities may be present in the water used to dilute the antifreeze concentrate. These are ions, more commonly known as "minerals", and they include chlorides, sulfates, carbonates, and metal cations such as calcium and magnesium. Chlorides and sulfates are corrosive, and calcium and magnesium cause scaling. In areas with very poor water quality, trace amounts of metals may also be present, especially iron and lead.
There are a number of conventional processes available for purifying and/or recycling antifreeze that has been contaminated. The most common conventional type of process available at present is based on a simple filtration method. The used antifreeze coolant is collected, pured into a filtration unit, filtered through a paper filter of varying porosities, discharged back into the vehicle, and then treated with a concentrated additive package to restore the inhibitor level. In this process, although the antifreeze has been "recycled" it has not been purified to any degree. It may appear cleaner as the filter will remove oil and solid contaminants large enough to be trapped by the filter which will improve its clarity, but the ionic species such as the impurities in the water, the acids, and the free metals will not have been removed and will be recycled back into the vehicle cooling system. Another conventional filtering process utilizes diatomaceous earth as the filtering medium. A diatomaceous earth filtering medium has a greater surface filtering area than a paper filter. This method is at least slightly more effective than paper or composition filtration, but the bulk of the impurities are still put back into the vehicle cooling system.
A problem with both of these conventional filtering processes is the lack of control over the inhibitor level in the final coolant solution. Both rely on adding a concentrated additive package to the system after the filtration step. Thus, the old additives retained in the filtered coolant plus the addition of concentrated inhibitors may lead to serious overconcentration. This may result in the precipitating or otherwise coming out of solution to deposit in cool, low lying areas of the vehicle cooling system, thus reducing flow and overall efficiency. They may also cause seal leaks such as in the water pump or plug filters in diesel cooling systems.
Another conventional approach to recycling antifreeze is the distillation process, which is one of the oldest chemical purification processes known. It is truly a "purification" process, unlike the filtration method, because it physically separates the water and glycol from all additives, impurities, contaminants, and even the dye. There are two ways of performing a distillation; namely, by the flash distillation process or by the simple distillation process.
The flash distillation process is a process in which the used antifreeze is added to a vessel preheated to a temperature above the boiling point of water and the glycol constituents. This essentially vaporizes the water and glycol and it is then condensed from a gaseous form back into a liquid. Non-volatile impurities are left behind in the distillation vessel. The condensate or distillate can then be checked for a glycol and inhibitor level and restored to a "recycled" condition. The advantage to this method is that it is much more effective than the simple filtration method at removing all of the contaminants, including ionic species.
The simple distillation process is very similar to the flash method with respect to the equipment employed. However, the used antifreeze is poured into the distillation chamber and then heat is applied slowly. This produces a boiling point range in which water will come off first to be collected separately, with the glycol boiling off second. If there are appreciable quantities of other glycols besides ethylene such as propylene, triethylene, or tetraethylene, the boiling point range of the antifreeze will be quite wide in terms of temperature. The simple distillation method is perhaps the slowest and most time consuming of the conventional processes but it is highly effective at removing impurities and providing pure water and glycol. It also formulates the waste into a solid form that is much less expensive to dispose of than drums of used antifreeze. The distilled water can also be used for other purposes, such as water for a car wash unit or battery water. The process does require operator manipulation and monitoring to determine when all of the water has all been condensed and when the glycol begins to distill.
Thus, what is needed and what has been invented by us is a fast, economical and ecologically advantageous method and apparatus for removing particulates and ions (i.e., cations and anions) from a liquid, such as the engine coolant liquid from the cooling system of a vehicle.